[Observium] sensors and devices up down false alarms

In the last months I'm starting to get some issues I cannot debug well . I have some alert of devices up&down that are not really going down even at ping check. I'm sure that there are no network issues as we are talking about near switch devices, I'm starting to think that I need to debug if our observium is starting to "saturate" and the performance get poor. is there something I can check to find if we need to tune observium ? Or best practices tI can use ?

CPU occupation graphs are kind of weird, processors occupation is different between Processors and Detailed Processors graphs :

any idea is welcome

Best Regards

Simone